Training Pots

[Barb59]

Hi. I'm new to bonsai. Can anyone explain to me the workings of bonsai training pots? Things like:

*How long should the plant remain in each pot before moving up?
*How do you know how many 'steps' (pot size changes) a particular plant will need to make?

And anything else I probably don't yet realise I'll need to know about them. Thanks.

[dmattar]

I'm about to give you the most frustrating answer but it goes for almost anything in bonsai : it depends. I was going to write a lot more but it might be too confusing, so I hope this gives you a bit of an answer.

Once you get into the ideaof oversimplified bonsai "training", you can view it as pretty much consisting of two phases which are not mutually exclusive - development and refinement. And seeing it this way can help understand what you are trying to get out of the repot. Development is where you try to build the main branching and trunk caliper while refinement is to build the finer structures. Generally speaking, increasing container size for more room is used to increase growth while downsizing the container is to slow it so you build finer structures.

A lot of things go into the decision to repot including soil type, age of the material, growth rate, species type, health and goals. If you are going to make a smaller tree, you spend less time in training pots and upsizing than if you were to make a larger tree from scratch. You only need to develop faster growth up until a point that you are happy with the size and proportions of the tree. After that, you can try to approximate the final size of the bonsai container while your tree is to be iteratively improved over time through ramification and fine twigging/branching etc.

Similarly, species or types of trees can dictate the repotting interval as coniferous species like junipers can be repotted every 3ish years + while a deciduous tree can be repotted roughly every two years and some fast growing tropical species like clerodendrum even more frequently. Generally, the rule of thumb is that the younger the material, the more frequently and aggressively you can repot the tree. Other areas of consideration are for the health of the tree and these can also include soil quality and the condition of the rootball. If the soil breaks down or the roots start circling and compacting everything so no water can penetrate, it might be a good idea to repot.

Other ideas which you can play with include the type of training pot. Normal nursery cans are OK options as they allow for good growth while not having the tree in the ground. Shallow nursery cans are a good option when you want to create a flatter root base but if you want good aeration, colanders or pond baskets can be good alternatives. There are also mica training pots that look like bonsai pots so they are an OK option aesthetically but can be pricey.

[Stu]

I often use plastic meat trays with holes skewered in the bottom for seedlings or cuttings. They keep the root-ball shallow.

[shibui]

Bonsai do not always go up in stages. I grow a lot of trees for bonsai in the ground so they go from a small pot into a huge pot (ground) for the growing phase then eventually back into smaller pots for refinement and finally into a bonsai pot for show.

There is no one answer for all species or even for different individuals in a particular species. So much depends on what you want to achieve (and here everyone has a different view of what size and shape they want) and how you want to get to that final outcome. Some may progress slowly through s,mall pots to make sure there are no big scars from trunk chops (takes much longer). Some will plant the trees in oversize pots to get increased growth. Others may use the garden to grow the plant to size quicker. Many great bonsai are actually collected from gardens or as wild plants and have never been in a pot until they are dug and potted up for the final styling as bonsai.

In bonsai there are many roads that can lead to the same place. One way does not fit all plants or all people.

[Barb59]

Thanks all for your replies.

I have two Leptospermum (Tea Tree) seedlings that I think would only be a few years old. They are about 20-25 cm tall and are pretty much as tall as I want them to get - they may even be a bit too tall. At the moment they are in pots that are 7cm X 15cm and 10cm X 8cm. One is very root bound and the other has roots coming out the bottom of the pot, so both need repotting.

I have bought a couple of wide-based plastic pots to transfer them into so that they can get used to a shallower bonsai pot. They are both round and about 23cm across at the widest point. How high do you think I should fill them with soil? They are big pots and I will cut them down to size to suit the plants.

Also, how long should they be in these shallower pots before being transferred into their final bonsai pot? From what I understand, plants can have about half their roots removed during root pruning. So does this mean that these plants should continue to be root pruned and repotted until I eventually get the amount of roots down to something that will fit in a bonsai pot?

Thanks.

[shibui]

I keep developing plants in grow pots until the trunk is the thickness I want it. Roots are much less important.
Trees in small pots thicken very slowly so your plan will end up taking years and years to get to a decent tree.
Roots are relatively easy to reduce, Just chop off excess roots after the tree has grown. Growing trunks is much slower and harder than reducing roots.

Height of a developing bonsai is also irrelevant because we can change that with a single chop. During development stages pre-bonsai can sometimes grow very tall and be chopped smaller than planned several times to build a decent trunk. Only right at the end do I worry about gradually growing the branches and apex out to my desired height.

It is certainly possible to grow a bonsai as you plan but you need to be aware that will take so many years. There are many ways to cut down the time and still achieve a similar result.

Root reduction of most natives is far better in warmer weather. You haven't given any indication of your location so hard to be specific for your conditions. In warmer areas growers are able to repot and root prune almost all year but in cooler areas like mine I repot natives in November and December.
Definitely continue to root prune regularly through the growing phase. Regular root pruning will develop lots of smaller feeder roots instead of a few long ones with feeders at the end.

[Barb59]

I'm not wanting to increase the trunk size at this stage, I'm just trying to learn things like wiring and styling for now.

I live in Melbourne so it gets chilly in winter. Perhaps I should get a heat mat so that I can repot plants year round?

Hmm increasing ramification is another thing I need to learn about...

Thanks for your help.

[one_bonsai]

I'm not wanting to increase the trunk size at this stage, I'm just trying to learn things like wiring and styling for now.

I live in Melbourne so it gets chilly in winter. Perhaps I should get a heat mat so that I can repot plants year round?

Hmm increasing ramification is another thing I need to learn about...

You can pretty much wire and style trees anytime of year but repotting and doing major root work is usually done in spring when the buds begin to swell. Using a heat may will not allow you to do major root work year round.

If you're starting out, do a lot of reading and watch YouTube videos. Then get yourself a Juniper and practicing styling and wiring, Don't worry too much about ramification at this stage.

[shibui]

I live in Melbourne so it gets chilly in winter. Perhaps I should get a heat mat so that I can repot plants year round?

Talking to some experienced native bonsai growers recently who tell me they can repot most natives any time of year, at least in inner suburbs and closer to the coast. Closer to the Dandenongs and outer suburbs further from the sea tend to be a bit cooler.

A heat mat could make a difference but I have not used one for this purpose. I'd rather just do things when it suits the plants and there's still plenty of other things to do for the rest of the year.

If you plan to hang around Ausbonsai you might like to add a location to your profile so you don't need to remember to tell us where you are every time you post. You can already see that a lot of things are very specific to where you are.

[Barb59]

If you plan to hang around Ausbonsai you might like to add a location to your profile so you don't need to remember to tell us where you are every time you post. You can already see that a lot of things are very specific to where you are.

Good idea. Location added.

Thanks.

[Barb59]

I plan to root prune and repot my two Leptospermum seedlings in the next few days. I'll probably remove about half their roots. What sort of after-care would be appropriate for them? I think I read somewhere that plants should be kept out of the sun for awhile afterwards. How long for? And is there anything else I need to do?

[shibui]

I usually root prune Aussie natives in warmer weather (Nov, Dec here) but experienced native growers in Melb tell me they can repot all year round as it is not as cold.
Don't read 'protected, as 'out of sun'. Sun is important for trees. Good light levels will help your trees grow new roots. I actually put mine straight back on the bench in the same position right after repotting.
Probably more important to make sure the roots do not dry out until new roots have got going and this may have been the origin of the 'place in shade' myth so water well and water often enough to make sure the new roots do not get dry.

If you do elect to place in shade just watch for new growth. When you see new shoots on top it is reasonable to assume that roots are also growing under the soil and they are ready to go home. Beware lots of new leaves have opened in shade. They will not be sun hardy and moving the tree suddenly back to sun will usually burn the leaves. Another good reason for putting straight back in the normal position.